Value of the Data •Eye-tracking is an objective method to observe student's task solving process, and can therefore be used to observe which information students utilize when solving tasks. This is crucial for understanding how task design can influence student's mathematical reasoning. • Eye-tracking data can be used to: ○ make additional analyses of students' eye movements. • Mathematics tasks can be used: ○ as a template to construct new tasks with the same reasoning requirements ○ to conduct replication studies.